CN111356833B

CN111356833B - Metal diaphragm damper and manufacturing method thereof

Info

Publication number: CN111356833B
Application number: CN201880073748.0A
Authority: CN
Inventors: 佐藤裕亮; 岩俊昭; 小川義博
Original assignee: Eagle Industry Co Ltd
Current assignee: Eagle Industry Co Ltd
Priority date: 2017-11-24
Filing date: 2018-11-20
Publication date: 2022-01-25
Anticipated expiration: 2038-11-20
Also published as: JPWO2019102983A1; US20200355311A1; EP3715617A4; CN111356833A; EP3715617A1; US11181220B2; WO2019102983A1

Abstract

A damper having excellent airtightness and a method of manufacturing the same. A metal diaphragm damper 1 includes: a disc-shaped damper body 2 having two diaphragms 4 and 5 between which gas is sealed, and each of which has a deformable portion 19 at the center thereof; two restraining members 6 and 7, respectively, are provided outside the deformable portions 19 of the two diaphragms 4 and 5. The metal diaphragm damper 1 includes: a first welded portion provided with a first welded layer WD1 and a second welded layer WD1, the first welded layer sealing the annular portion 25 of the restriction member 6 and the outer edge portion 20 of the membrane 4, the second welded layer sealing the annular portion 25 of the further restriction member 7 and the outer edge portion 20 of the further membrane 5. The metal diaphragm damper 1 further includes: a second welded portion provided with a weld layer WD2 that seals the annular portions 25 of the two restricting members 6 and 7.

Description

Metal diaphragm damper and manufacturing method thereof

Technical Field

The present invention relates to a metal diaphragm damper that absorbs pulsation generated by conveying liquid by a pump or the like, and a manufacturing method thereof.

Background

For example, when driving an engine or the like, a high-pressure fuel pump is used in order to compress and deliver fuel supplied from a fuel tank to an injector. The high-pressure fuel pump pressurizes and discharges fuel by reciprocating movement of a plunger driven by rotation of a camshaft of an internal combustion engine.

As a mechanism of pressurizing and discharging fuel in the high-pressure fuel pump, first, a suction process is performed in which when the plunger descends, the suction valve opens, and fuel is sucked from a fuel chamber formed on the inlet side to the pressurizing chamber. Subsequently, a volume adjustment process is performed in which a portion of the fuel in the pressurizing chamber is returned to the fuel chamber when the plunger rises. After the suction valve is closed, a pressurization process is performed in which the fuel is pressurized when the plunger is further raised. As described above, the high-pressure fuel pump repeats the cycle of the suction process, the volume adjustment process, and the pressurization process to pressurize and discharge the fuel to the injector side. By driving the high-pressure fuel pump in this way, pulsation is generated in the fuel chamber.

In such a high-pressure fuel pump, a metal diaphragm damper that reduces pulsation generated in the fuel chamber is incorporated in the fuel chamber. For example, patent citation 1 discloses a metal diaphragm damper including a disc-shaped damper body in which gas is sealed between two diaphragms. The damper body includes a deformable portion disposed at a center thereof. The deformable portion receives the fuel pressure associated with the pulsation and elastically deforms, thereby making the capacity of the fuel chamber variable to reduce the pulsation.

In the metal diaphragm damper disclosed in patent citation 1, the restricting member is provided outside the deformable portions of the two diaphragms so as to sandwich the damper body, and the restricting member restricts deformation of the damper body in the expansion direction. Therefore, stress repeatedly acting in the vicinity of the outer diameter edges of the deformable portions of the two diaphragms can be suppressed, and the durability of the damper main body is improved.

CITATION LIST

Patent document

Patent document 1: JP 2014-240658A (page 8, FIG. 5).

Disclosure of Invention

The technical problem to be solved by the invention is as follows: here, in the metal diaphragm damper of patent citation 1, the restricting members provided to sandwich the damper main body each include, at the outer edge, a ring-shaped portion formed in parallel with the outer edge portions of the two diaphragms. The outer edge portions of the two membrane sheets, the annular portion of one of the restricting members, and the annular portion of the other restricting member (i.e., the side end portions of the four plate portions) are fixed over the entire circumference by welding. As described above, in the case of integrally welding the four plate portions, it is necessary to weld three boundary portions consisting of the first boundary portion between the annular portion of one of the restricting members and the outer edge portion of one of the two diaphragms, the second boundary portion between the outer edge portions of the two diaphragms, and the third boundary portion between the outer edge portion of the other of the two diaphragms and the annular portion of the other restricting member in a state where the four plate portions are placed on each other. Since welding is performed over a wide area, welding accuracy between the diaphragms that are particularly required to be airtight is reduced, resulting in a risk that airtightness cannot be ensured.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a metal diaphragm damper having excellent airtightness and a method for manufacturing the same.

In order to solve the technical problems, the invention adopts the technical scheme that: in order to solve the above problems, a metal diaphragm damper according to the present invention includes: a damper main body formed in a disc shape and including a first diaphragm and a second diaphragm, a gas being sealed between the first diaphragm and the second diaphragm, and each of the first diaphragm and the second diaphragm having a deformable portion at a center thereof; a first restriction member provided outside the deformable portion of the first diaphragm; a second restriction member provided outside the deformable portion of the second diaphragm; a first welding portion provided with a first welding layer formed by welding to seal the annular portion of the first restriction member and the outer edge portion of the first diaphragm and a second welding layer formed by welding to seal the annular portion of the second restriction member and the outer edge portion of the second diaphragm; and a second welding portion provided with a welding layer formed by welding to seal the annular portions of the first and second restriction members.

According to the above configuration of the metal diaphragm damper, the restriction member restricts the deformation of the damper main body in the expansion direction, and therefore the durability of the damper main body can be improved. Since the ring-shaped portion of the first restriction member and the outer edge portion of the first diaphragm are sealed by the first weld layer of the first weld portion, the ring-shaped portion of the second restriction member and the outer edge portion of the second diaphragm are sealed by the second weld layer of the first weld portion, and the ring-shaped portions of the first restriction member and the second restriction member are sealed by the weld layer of the second weld portion, the area in which welding is performed is small. This means that welding with excellent execution accuracy can be performed, and airtightness is also excellent.

Preferably, an outer diameter of the annular portion of the first restriction member may be formed larger than an outer diameter of the first diaphragm, an outer diameter of the annular portion of the second restriction member may be formed larger than an outer diameter of the second diaphragm, and the second weld portion may be located radially outward with respect to an outer edge portion of the first diaphragm and an outer edge portion of the second diaphragm. In this case, in the process of sealing the damper main body, only the annular portions of the first and second restricting members need to be welded, and the outer edge portions of the first and second diaphragms do not interfere. Therefore, the annular portions of the first and second restriction members can be welded with high accuracy.

Preferably, each of the annular portion of the first restriction member and the annular portion of the second restriction member may have a recess respectively formed in each of inner surfaces of the annular portion facing each other on a radially inner side of the annular portion, and the outer edge portion of the first diaphragm and the outer edge portion of the second diaphragm may be respectively disposed in the recesses of the first restriction member and the second restriction member. In this case, the alignment between the first restriction member and the second diaphragm and the other alignment between the second restriction member and the second diaphragm can be independently performed, and thus the welding work in forming the first and second weld layers of the first welded portion can be easily performed.

Preferably, the depth of the recess of the first restriction member and the recess of the second restriction member in the axial direction may be substantially equal to the thickness of the outer edge portion of the first diaphragm and the outer edge portion of the second diaphragm, respectively. In this case, the outer edge portions of the first and second diaphragms contact each other in a state where the annular portions of the first and second limiting members contact each other. This means that the movements of the first and second limiting members and the first and second diaphragms in opposite directions can be limited to each other. Therefore, the durability of the first welded portion that fixes the annular portions of the first and second restricting members to the outer edge portions of the first and second diaphragms is excellent.

Preferably, the first diaphragm may include a curved portion that is formed between the deformable portion and the outer edge portion of the first diaphragm and that protrudes from the annular portion of the first restriction member in a direction opposite to a protruding direction of the deformable portion of the first diaphragm in a natural state of the first diaphragm. Similarly, the second diaphragm may include a curved portion that is formed between the deformable portion and the outer edge portion of the second diaphragm and that protrudes from the annular portion of the second restriction member in a direction opposite to a protruding direction of the deformable portion of the second diaphragm in a natural state of the second diaphragm. In this case, in a state where the annular portions of the first and second restricting members are in contact with each other, the curved portion of the first diaphragm and the curved portion of the second diaphragm are pressed against each other, and a reaction force of the pressing force brings about the following states: stress to the inner surface side of each annular portion of the first and second limiting members acts on each outer edge portion of the first and second diaphragms, and therefore, durability of the first welded portion that fixes each annular portion of the first and second limiting members to each outer edge portion of the first and second diaphragms is excellent.

In order to solve the above problems, a metal diaphragm damper according to the present invention includes: a damper body having a diaphragm and a plate-shaped base member, a gas being sealed between the diaphragm and the plate-shaped base member, the diaphragm being provided with a deformable portion at a center thereof; a restriction member provided outside the deformable portion of the diaphragm; a first welded portion provided with a welded layer formed by welding to seal the annular portion of the restriction member and the outer edge portion of the diaphragm; and a second welding portion provided with a welding layer formed by welding to seal the annular portion of the restricting member and the base member. According to such a configuration of the metal diaphragm damper, the restricting member restricts the deformation of the diaphragm in the expansion direction, and therefore, the durability of the damper main body can be improved. The annular portion of the regulating member and the outer edge portion of the diaphragm are sealed by a first welding portion, and the annular portion of the regulating member and the base member are sealed by a second welding portion. Therefore, the area where welding is performed is small. This means that welding with excellent accuracy can be performed, and airtightness is also excellent.

In order to solve the above problems, there is provided a method of manufacturing a metal diaphragm damper of the present invention, the metal diaphragm damper comprising: a damper body having a disc shape and including a first diaphragm and a second diaphragm, a gas being sealed between the first diaphragm and the second diaphragm, and each of the first diaphragm and the second diaphragm having a deformable portion at a center thereof; a first restriction member provided outside the deformable portion of the first diaphragm; a second restraining member disposed outside of the deformable portion of the second diaphragm, wherein the method comprises: a first welding step of fixing the annular portion of the first restriction member to the outer edge portion of the first diaphragm by welding; a second welding step of fixing the annular portion of the second restriction member to the outer edge portion of the second diaphragm by welding; a third welding step of fixing the annular portion of the first restriction member and the annular portion of the second restriction member by welding after the first step and the second step. According to the above method, the first and second restriction members can restrict the deformation of the damper main body in the expansion direction, and the durability of the damper main body can be improved. After the ring-shaped portion of the first restriction member is fixed to the outer edge portion of the first membrane sheet in the first welding step and the ring-shaped portion of the second restriction member is fixed to the outer edge portion of the second membrane sheet in the second welding step, the ring-shaped portions of the first restriction member and the second restriction member are fixed to each other in the third welding step. Therefore, the area where welding is performed is small, welding with excellent accuracy can be performed, and as a result, airtightness is excellent.

Preferably, the first welding step and the second welding step may be performed in an atmosphere made of air, and the third welding step may be performed in an atmosphere made of a gas sealed between the first membrane and the second membrane. In this case, the first welding step performed in the atmosphere made of air can suppress generation of welding fumes in the second welding step, and therefore can suppress obstruction of the welding work due to the welding fumes. That is, welding with excellent accuracy can be performed.

Drawings

Fig. 1 is a sectional view showing a high-pressure fuel pump in which a metal diaphragm damper according to a first embodiment of the present invention is installed.

Fig. 2 is a sectional view illustrating a metal diaphragm damper according to an embodiment.

Fig. 3 is an exploded sectional view illustrating a metal diaphragm damper according to an embodiment.

Fig. 4(a) is an exploded sectional view showing a state where one diaphragm is placed on one restricting member in the first embodiment.

Fig. 4(b) is an exploded sectional view showing a state in which fixing of the diaphragm to the restricting member by welding is completed in embodiment one.

Fig. 5 is an exploded sectional view showing a state in which fixing of the restriction members to each other is completed in the first embodiment.

Fig. 6 is a partially enlarged sectional view showing the structure of the diaphragm at a high pressure depicted by a solid line and a low pressure depicted by a broken line in the first embodiment.

Fig. 7(a) is a sectional view showing a two-metal diaphragm damper according to an embodiment of the present invention before assembly.

Fig. 7(b) is a sectional view showing the two-metal diaphragm damper according to the embodiment after assembly.

Fig. 8(a) is a sectional view showing a trimetal diaphragm damper during assembly according to an embodiment.

Fig. 8(b) is a sectional view showing the trimetal diaphragm damper according to the embodiment after assembly.

Fig. 9(a) is a sectional view showing a four-metal diaphragm damper according to the embodiment before assembly.

Fig. 9(b) is a sectional view showing the four-metal diaphragm damper according to the embodiment after assembly.

Fig. 10 is a sectional view showing a first example modification of a metal diaphragm damper corresponding to a metal diaphragm damper according to embodiment five of the invention.

Fig. 11 is a sectional view showing a second example modification of the metal diaphragm damper corresponding to the metal diaphragm damper according to the sixth embodiment of the invention.

Detailed Description

Hereinafter, a mode of implementing the metal diaphragm damper and the method of manufacturing the same according to the present invention will be described based on embodiments.

Example one

Referring to fig. 1 to 6, a metal diaphragm damper according to a first embodiment of the present invention will be described.

As shown in fig. 1, a metal diaphragm damper 1 according to a first embodiment of the invention is mounted in a high-pressure fuel pump 10 that pressurizes and delivers fuel supplied from a fuel tank to an injector side through a fuel inlet, not shown. The high-pressure fuel pump 10 pressurizes and discharges fuel by reciprocating a plunger 12 driven by rotation of an unillustrated camshaft of the internal combustion engine.

The mechanism of pressurizing and discharging fuel in the high-pressure fuel pump 10 is, first, to perform a suction process in which, when the plunger 12 descends, the suction valve 13 opens and fuel is sucked from the fuel chamber 11 formed on the fuel inlet side to the pressurizing chamber 14. Subsequently, a volume adjustment process is performed in which a part of the fuel in the pressurizing chamber 14 is returned to the fuel chamber 11 when the plunger 12 is raised, and a pressurization process is performed after the suction valve 13 is closed, in which the fuel is pressurized when the plunger 12 is further raised.

As described above, the high-pressure fuel pump 10 repeats the cycle of the suction process, the volume adjustment process, and the pressurization process, and the high-pressure fuel pump 10 pressurizes the fuel, opens the discharge valve 15, and discharges the fuel to the injector side. At this time, pulsation that repeats high pressure and low pressure is generated in the fuel chamber 11. The metal diaphragm damper 1 is for reducing pulsation generated in the fuel chamber 11 of the above-described high-pressure fuel pump 10.

As shown in fig. 2, the metal diaphragm damper 1 includes: a damper main body 2 composed of a diaphragm 4 and a diaphragm 5; and a cover member 3 composed of a restricting member 6 and a restricting member 7 respectively disposed radially outside the

diaphragms

4 and 5.

By press working a metal plate of the same metal, the

diaphragms

4 and 5 are formed into disc-like shapes having substantially uniform thicknesses and almost the same shape. On the center side in the radial direction, that is, in the center of the

diaphragms

4 and 5, deformable portions 19 are formed, respectively. Radially outside the deformable portions 19, flat annular outer edge portions 20 extending in the radially outside direction from the deformable portions 19 are formed, respectively.

Next, the diaphragm 4 and the diaphragm 5 will be described. Note that since the

diaphragms

4 and 5 are the same shape, one diaphragm 4 will be described here, and description of the other diaphragm 5 will be omitted.

The deformable portion 19 of the membrane 4 is mainly constituted by: a third curved portion 24 continuously connected to a radially inner portion of the outer edge portion 20; a first curved portion 22 located on a central side (i.e., radially inner side); and a second curved portion 23 located between the third curved portion 24 and the first curved portion 22.

The first curved portion 22, the second curved portion 23, and the third curved portion 24 are all formed with a certain curvature. The first curved portion 22 is formed to protrude to the outside of the diaphragm 4 (i.e., the side of the restricting member 6 in fig. 2), the second curved portion 23 is formed to protrude to the inside of the diaphragm 4, and the third curved portion 24 is formed to protrude to the outside of the diaphragm 4.

Next, the restricting member 6 and the restricting member 7 will be described. Note that since the

restriction members

6 and 7 have the same shape, one restriction member 6 will be described herein, and the description of the other restriction member 7 will be omitted.

As shown in fig. 3, the restricting member 6 includes: an annular portion 25 having a diameter larger than the outer diameter of the diaphragm 4; and a side wall portion 27 and a bottom portion 28 continuously connected to the radially inner side of the annular portion 25. The side wall portion 27 and the bottom portion 28 are formed in a bottomed cylindrical shape, and therefore, the restriction member 6 is formed in a shape approximating a hat when viewed in cross section. As shown in fig. 2, the bottom portion 28 is disposed to be spaced apart from the deformable portion 19 of the diaphragm 4 by a predetermined distance. Therefore, in the case where the deformable portion 19 of the diaphragm 4 is deformed by a predetermined amount in the expanding direction, the deformable portion 19 contacts the bottom portion 28 of the restriction member 6 to restrict the deformation of the diaphragm 4. That is, by adjusting the distance between the deformable portion 19 and the bottom portion 28, the allowable deformation amount of the diaphragm 4 in the expanding direction can be set.

The annular portion 25 of the restriction member 6 has a flat annular shape parallel to and opposed to the annular portion 25 of the restriction member 7. The annular portion 25 has an inner surface 25a facing the annular portion 25 of the restricting member 7, and is provided with a recess 29 formed on the inner surface 25a to extend continuously in the circumferential direction. The recess 29 is formed such that the recess 29 is recessed in the thickness direction of the annular portion 25 and is open radially inward of the annular portion 25.

On the bottom portion 28 of the cover member 3 constituted by the

restriction members

6 and 7, a plurality of holes 30 are formed, and the outside of the cover member 3 communicates with the inside through these holes 30.

As shown in fig. 1, a plurality of support members 31 are fixed to the inner wall of the fuel chamber 11. The support member 31 is almost U-shaped in cross section and has an opening 31a directed in the radially inner direction of the fuel chamber 11 (see fig. 6). The annular portion 25 of the restriction member 6 and the annular portion 25 of the restriction member 7 constituting the cover member 3 are fitted into the opening 31a, and as a result, the cover member 3 is supported in the fuel chamber 11.

Next, a manufacturing process of the metal diaphragm damper 1 will be described. As shown in fig. 4(a), first, the outer edge portion 20 of the diaphragm 4 is set in the recess 29 of the annular portion 25 of the restriction member 6. Subsequently, as shown in fig. 4(b), in the atmosphere made of air, the components are fixed to each other by welding over the entire circumference in a state where the bottom surface 29a (see fig. 3) of the recess 29 and the outer surface 20a (see fig. 3) of the outer edge portion 20 of the diaphragm 4 are in surface contact with each other (referred to as a first welding step).

In the present embodiment, laser welding is used for the first welding step. In detail, the laser beam is applied from the inside of the outer edge portion 20 to the inner surface 20b of the outer edge portion 20 of the diaphragm 4, and the boundary portion of the bottom surface 29a in the recess 29 of the restriction member 6 and the bottom surface 20a at the outer edge portion 20 of the diaphragm 4 is melted, so that the weld layer (i.e., the first half portion of the first weld portion) WD1 is formed to pass through the outer edge portion 20 of the diaphragm 4 and sink into the ring-shaped portion 25 of the restriction member 6 (see fig. 4 (b)). Note that the welding step is not limited to laser welding, and may be performed by welding means including gas welding, arc welding, friction stir welding, or the like. However, the laser welding has a characteristic that the welding deformation is small on the inner surface 20b of the outer edge portion 20 of the diaphragm 4.

As shown in fig. 3, the diameter W1 defined by the inside surface 29b on the outer diameter side of the recess 29 of the annular portion 25 of the restricting member 6 is substantially equal to the outer diameter W2 of the outer edge portion 20 of the diaphragm 4, and therefore, the movement of the diaphragm 4 in the radial direction in the recess 29 of the restricting member 6 can be restricted. Therefore, when the first welding step is performed, the diaphragm 4 is correctly positioned with respect to the restricting member 6, and excellent welding workability can be provided.

Similarly, in the atmosphere of air production, these components are fixed by welding over the entire circumference in a state where the bottom surface 29a of the recess 29 of the annular portion 25 of the other restricting member 7 and the outer surface 20a of the outer edge portion 20 of the other membrane 5 are in surface contact with each other, and another welding layer WD1 is formed at the boundary portion between the annular portion 25 of the restricting member 7 and the outer edge portion 20 of the membrane 5 (referred to as a second welding step).

Next, in an atmosphere made of a gas of a predetermined pressure sealed between the

diaphragms

4 and 5, the restricting member 6 and the restricting member 7 which have been fixed to the

diaphragms

4 and 5 are placed symmetrically to each other, specifically, these components are fixed and welded over the entire circumference in a state where the opposing surface 25a of the annular portion 25 of the restricting member 6 is in surface contact with the opposing surface 25a of the annular portion 25 of the restricting member 7 (referred to as a third welding step), and a weld layer (i.e., a second weld) WD2 is formed at an outermost circumferential boundary portion between the inner surface 25a of the restricting member 6 and the inner surface 25a of the restricting member 7 (see fig. 5).

By welding the annular portion 25 of the restriction member 6 to the annular portion 25 of the restriction member 7, the assembly of the cover member 3 and the assembly of the damper main body 2 are completed.

The outer edge portion 20 of the diaphragm 4 and the annular portion 25 of one restricting member 6 are fixed to each other over the entire circumference by the first welding layer WD1 and are hermetically sealed in the first welding step, and similarly, the outer edge portion 20 of the other diaphragm 5 and the annular outer peripheral portion 25 of the other restricting member 7 are fixed to each other over the entire circumference by the second welding layer WD1 and are hermetically sealed in the second welding step, and in the third welding step, the annular portion 25 of the restricting member 6 and the annular portion 25 of the restricting member 7 are fixed to each other. As a result, the fixation of the diaphragm 4 to the diaphragm 5 is completed over the entire circumference by the weld layer WD2 and is hermetically sealed, thus ensuring the airtightness of the damper body 2.

In the closed space inside the damper main body 2, a gas of a predetermined pressure, for example, composed of argon or helium, is sealed. Note that the damper main body 2 adjusts the volume change amount by the internal pressure of the gas sealed inside, and therefore a desired pulsation absorbing performance can be obtained.

In the cover member 3, since a plurality of holes 30 are formed on the bottom 28 of the restriction member 6 and the bottom 28 of the restriction member 7, the outside of the cover member 3 (i.e., the internal space of the fuel chamber 11) communicates with the inside of the cover member 3 (i.e., the space around the damper body 2) through the plurality of holes 30. Therefore, the fuel pressure associated with the pulsation that is introduced into the fuel chamber 11 and repeatedly applies the high pressure and the low pressure acts directly on the damper body 2.

Next, pulsation absorption of the metal diaphragm damper 1 when fuel pressure associated with pulsation of repeated high and low pressures is received will be described with reference to fig. 6.

As shown in fig. 6, the fuel pressure associated with the pulsation changes from low pressure to high pressure, and the fuel pressure in the fuel chamber 11 is applied to the diaphragm 4, and first, the first curved portion 22 having a dome shape with a large radius of curvature and small rigidity is mainly deformed. Note that the first curved portion 22 is flattened inward, and the gas in the damper main body 2 is compressed.

In detail, the first curved portion 22 is deformed in a direction toward the inside of the diaphragm 4 due to the fuel pressure as the external pressure, and is deformed to expand in a radially outward direction, and stress is applied from the first curved portion 22 of the diaphragm 4 to a portion on the outer diameter side in the radially outward direction.

The stress applied to the outer diameter side of the diaphragm 4 in the radially outward direction is transmitted along the surface of the diaphragm 4. Since the second curved portion 23 is a curved surface that is concave in the inward direction, the stress follows the shape of the second curved portion 23 in the radial direction inside from the bottom T2 of the second curved portion 23 in the axial direction, and also acts in a direction toward the inside of the diaphragm 4. As shown in fig. 6, due to the force applied in the inward direction and the stress in the radially outward direction, the second curved portion 23 is deformed so that the bottom point T2 in the axial direction is moved in the direction toward the inside of the diaphragm 4 and in the radially outward direction.

As described above, the second curved portion 23 is deformed such that the bottom point T2 thereof moves in the direction toward the inside of the diaphragm 4 and in the radially outward direction, and on the third curved portion 24 extending to the second curved portion 23, in addition to the stress in the radially outward direction, the force pulling the third curved portion 24 in the direction toward the inside of the diaphragm 4 acts on the third curved portion 24 from the apex point T3 thereof also in the radially inward direction. Therefore, the third curved portion 24 is deformed so that the radius of curvature is smaller than that at the time of low pressure, and the third curved portion 24 is deformed so as to protrude on the outer diameter side.

Therefore, the stress in the radially outward direction acting on the first curved portion 22 is converted into a force that reduces the radius of curvature of the third curved portion 24, and a part of the stress in the radially outward direction is absorbed by the deformation of the third curved portion 24, so that the stress applied to the diaphragm 4 is dispersed, and thus the diaphragm 4 is prevented from cracking.

The third curved portion 24 of the diaphragm 4 is separated from the side wall portion 27 of the restricting member 6, and the side wall portion 27 of the restricting member 6 does not interfere with the deformation of the third curved portion 24 in the radially outward direction due to the fuel pressure.

As described above, since the diaphragm 4 is configured to be able to absorb a part of the stress in the radially outward direction by the deformation of the third curved portion 24, the annular portion 25 of the restricting member 6 is located outside the outer edge portion 20 of the diaphragm 4, and is able to disperse the stress applied to the diaphragm 4 in the radially outward direction while restricting the deformation of the outer edge portion 20 in the radially outward direction.

As described above, in order to ensure the airtightness of the damper main body 2, in the metal diaphragm damper 1 according to the present embodiment, since the ring-shaped portions 25 of the restriction member 6 and the restriction member 7, which have been fixed to the outer edge portions 20 of the

diaphragms

4 and 5, respectively, only need to be welded to each other, the area where the weld layer WD2 formed by welding is formed is relatively small, and the welding work is easy. In addition, since the penetration in welding hardly changes, airtightness can be reliably ensured.

Since the outer diameters of the annular portions 25 of the restricting

members

6 and 7 are formed larger than the outer diameters W2 of the

diaphragms

4 and 5, the two annular portions 25 of the restricting

members

6 and 7 only need to be welded to each other when the damper body 2 is sealed. Since the outer edge portions 20 of the two

diaphragms

4 and 5 do not interfere, the annular portions 25 of the restricting

members

6 and 7 can be welded to each other with high accuracy, and the area where welding is performed can be reduced.

As shown in fig. 3, since the depth H1 in the axial direction of the recess 29 of the annular portion 25 of the restricting member 7 is formed to be slightly larger than the thickness H2 in the axial direction of the outer edge portion 20 of the diaphragm 5 (i.e., H1 > H2), even in the case where irregularities are generated on the inner surface 20b of the outer edge portion 20 of the diaphragm 5 by welding, for example, in the first welding step, the irregularities are hard to protrude from the recess 29. Therefore, the diaphragm 4 and the inner surface 20b of the outer edge portion 20 of the diaphragm 5 can be prevented from contacting each other, and the inner surface 25a of the annular portion 25 of the restricting member 6 and the inner surface 25a of the annular portion 25 of the restricting member 7 can be reliably surface-contacted with each other in the entire circumferential direction. When the inner surfaces 25a are brought into surface contact, the welding work in the third welding step is easy, and the strength of the metal diaphragm damper 1 can be increased to resist the stress in the torsional direction (i.e., the circumferential direction) acting on the welded portions of the annular portion 25 of the restricting member 6 and the annular portion 25 of the restricting member 7.

Since the outer diameter W1 of the recess 29 defined by the radially outer inner side surface 29b of the recess 29 of the annular portion 25 of the restricting member 6 has almost the same diameter as the outer diameter W2 of the outer edge portion 20 of the diaphragm 4 (i.e., W1 ═ W2), it is possible to receive a force that causes the diaphragm 4 to expand in the radially outward direction due to the deformation of the diaphragm 4 by the fuel pressure on the radially outer inner side surface 29b of the recess 29 of the annular portion 25 of the restricting member 6. Therefore, stress concentration on the weld layer WD1, which is the weld site of the restricting member 6 and the diaphragm 4, can be prevented, and the weld strength of the first weld layer WD1 can be maintained.

In addition, as shown in fig. 6, the annular portion 25 of the restricting member 6 and the annular portion 25 of the restricting member 7 of the cover member 3 are fitted in the opening 31a of the support member 31, and the movement in the direction in which the annular portion 25 of the restricting member 6 is separated from the annular portion 25 of the restricting member 7 can be restricted. Therefore, the welding strength of the weld layer WD2, which is the welding portion between the annular portion 25 of the restriction member 6 and the annular portion 25 of the restriction member 7, can be maintained.

In order to inject the gas into the inside of the damper main body 2, a third welding step (in which the annular portion 25 of the restricting member 6 is welded to the annular portion 25 of the restricting member 7) is performed in an atmosphere made of the gas. In detail, in a small room (or chamber) filled with gas of a predetermined pressure for welding work, the third welding step is performed.

At this time, the conventional metal diaphragm damper 1 has the following problems: since the four plate bodies (the outer edge portions of the two diaphragms, the annular portion of the upper support member, and the annular portion of the lower support member) are fixed and welded at the same time, the amount of molten metal required for welding is increased, and welding fumes generated in welding are increased. The increase of welding fumes has the following problems: in the case of using laser welding, welding fumes obstruct the light beam and reduce welding accuracy, and further, there is a risk of generating problems such as reduction in productivity due to the need to frequently clean the inside of a room where welding work is performed.

Compared to such a conventional metal diaphragm damper, the metal diaphragm damper 1 according to the present embodiment may have the following advantages: the generation of welding fume can be suppressed, the obstruction of light beam in laser welding can be suppressed, and the number of times of cleaning the inside of a small room where welding work is performed can be reduced. The reason for the advantage is that in the atmosphere of the gas sealed in the damper main body 2, it is only necessary to fix the two portions, i.e., the annular portion 25 of the adjustment member 6 and the annular portion 25 of the adjustment member 7, by welding (i.e., the third welding step). In addition, since the fixing of the restricting member 6 to the diaphragm 4 by welding (i.e., the first welding step) and the fixing of the restricting member 7 to the diaphragm 5 by welding (i.e., the second welding step) are previously performed in an atmosphere made of air, the above-described advantages are more apparent.

Since the annular portion 25 of the restriction member 6 and the annular portion 25 of the restriction member 7 have the distal ends on the outer diameter side formed to be thin, the region where welding is performed is small, and the welded layer WD2 excellent in accuracy can be easily formed. Further, since the outer edge portion of the lid member 3 formed by the annular portion 25 of the regulating member 6 and the annular portion 25 of the regulating member 7 has a tapered shape that becomes thinner toward the tip end thereof, the boundary portion of the annular portion 25 of the regulating member 6 and the annular portion 25 of the regulating member 7 (i.e., the portion where the weld layer WD2 is formed) is easily distinguished, and the work efficiency of the third welding step is excellent.

Example two

Next, a metal diaphragm damper according to a second embodiment of the invention will be described with reference to fig. 7(a) and 7 (b). Note that description of repetitive parts having the same configuration as those in the embodiment is omitted.

As shown in fig. 7(a) and 7(b), in the metal diaphragm damper 41, the depth H3 in the thickness direction of the recess 45 of the annular portion 44 of the restricting member 42A is formed to be almost the same size as the thickness H4 of the outer edge portion 48 of the diaphragm 46A (H3 — H4).

Therefore, in a state where the annular portion 44 of the restriction member 42A is fixed to the annular portion 44 of the restriction member 42B by welding, the inner surface 48a of the outer edge portion 48 of the membrane 46A and the inner surface 48a of the outer edge portion 48 of the membrane 46B are in surface contact with each other over the entire circumference. Accordingly, since the inner surfaces 48a of the outer edge portions 48 of the two

diaphragms

46A and 46B contact each other and restrict the movement of each other in opposite directions, the durability of the first and second welding layers WD1 (see fig. 4(B)) that fix the annular portion 44 of the restriction member 42A to the outer edge portion 48 of the diaphragm 46A and fix the annular portion 44 of the restriction member 42B to the outer edge portion 48 of the diaphragm 46B by welding is excellent.

Note that since laser welding can be used for the first welding step to suppress welding deformation in the opposing surfaces 48a of the outer edge portions 48 of the

diaphragms

46A and 46B, the opposing surfaces 48a of the outer edge portions 48 of the diaphragms 46A and the opposing surfaces 48a of the outer edge portions 48 of the diaphragms 46B can be surface-contacted over the entire circumference only by surface treatment such as simple polishing.

EXAMPLE III

Next, a metal diaphragm damper according to a third embodiment of the present invention will be described with reference to fig. 8(a) and 8 (b). Note that description of repetitive parts having the same configuration as those in the embodiment is omitted.

As shown in fig. 8(a), the diaphragm 56A partially constituting the metal diaphragm damper 51 includes a bent portion 57 between the deformable portion 59 and the outer edge portion 58, and in the natural state of the diaphragm 56A, the bent portion 57 protrudes from the annular portion 54 of the restriction member 52A in a direction opposite to the protruding direction of the deformable portion 59 of the diaphragm 56A.

The depth H5 in the axial direction of the recess 55 formed on the annular portion 54 of the restricting member 52A is smaller than the distance H6 in the axial direction from the outer edge portion 58 of the diaphragm 56A to the bottom point (i.e., the lowest point) of the curved portion 57 (i.e., H5 < H6). Therefore, as shown in fig. 8(B), in a state where the annular portion 54 of the restriction member 52A is in contact with the annular portion 54 of the restriction member 52B, the bent portion 57 of the diaphragm 56A and the bent portion 57 of the diaphragm 56B are pressed and compressed against each other.

Accordingly, the curved portions 57 of the

diaphragms

56A and 56B are pressed against each other, and the reaction force of the pressing force brings the following states: on the outer edge portion 58 of the diaphragm 56A and the outer edge portion 58 of the diaphragm 56B, a stress on the bottom surface 55a of the recess 55 of the annular portion 54 of the restriction member 52A and a stress on the bottom surface 55a side of the recess 55 of the annular portion 54 of the restriction member 52B act. It is possible to maintain the durability of the first and second welded layers WD1 (see fig. 4(B)) which are the welded portions of the outer edge portions 58 of the

diaphragms

56A and 56B to the annular portion 54 of the restriction member 52A and the welded portions of the edge portions 58 of the diaphragm 56B to the annular outer peripheral portion 54 of the restriction member 52B. Note that the depth H5 in the axial direction of the recess 55 of the annular portion 54 of the restricting member 52A is formed slightly larger than the thickness in the axial direction of the outer edge portion 58 of the diaphragm 56A.

Example four

Next, a metal diaphragm damper according to a fourth embodiment of the present invention will be described with reference to fig. 9(a) and 9 (b). Note that description of repetitive parts having the same configuration as those in the embodiments is omitted.

As shown in fig. 9(a), similarly to the third embodiment in which the curved portion 67 protrudes inward in the axial direction of the outer edge portion 68 in a natural state, each of the

diaphragms

66A and 66B partially constituting the metal diaphragm damper 61 includes the curved portion 67 between the deformable portion 69 and the outer edge portion 68. The depth H7 in the axial direction of the recess 65 formed on the annular portion 64 of the restricting member 62A is almost the same size as the thickness H8 of the outer edge portion 68 of the diaphragm 66A (i.e., H7 — H8).

According to the above configuration, as shown in fig. 9(B), in a state where the annular portion 64 of the restriction member 62A is in contact with the annular portion 64 of the restriction member 62B, the curved portions 67 of the

diaphragms

66A, 66B are pressed against each other to be compressed into a flat shape. Since the curved portions 67 of the

diaphragms

66A and 66B press against each other, the reaction force of the pressing force produces the following state: the stress on the bottom surface 65a of the recess 65 of the annular portion 64 of the restriction member 62A and the stress on the bottom surface 65a of the recess 65 of the annular portion 64 of the restriction member 62B act on the outer edge portions 68 of the

diaphragms

66A, 66B. On the outer diameter side of the curved portion 67, the inner surfaces 68a of the outer edge portions 68 are in surface contact with each other and restrict movement in opposite directions to each other. Therefore, the durability of the first and second welding layers WD1 (see fig. 4(b)) can be effectively maintained.

As described above, the embodiments according to the present invention are described with reference to the drawings. The specific configuration is not limited to these embodiments, and even if modifications and additions are made within the scope of the invention, these modifications and additions are also included in the invention.

For example, in the embodiment, the first and second welding layers WD1 are formed by laser welding such that a portion of the outer edge portions 20 of the

diaphragms

4 and 5 and a portion of the annular portions 25 of the

restriction members

6 and 7 are respectively melted and mixed. Similarly, the welding layer WD2 is formed by laser welding so that a part of the annular portions 25 of the

restriction members

6 and 7 is melted and mixed. However, without being limited to these, the first and second welding layers WD1 and WD2 may be formed by fusion of a portion of the diaphragm and a filler metal, another filler metal, or a portion of the limiting member.

The

diaphragms

4 and 5 do not have to be of the same shape. Similarly, the restraining

members

6 and 7 need not be the same shape.

As in the first example modification shown in fig. 10 (which may be referred to as embodiment five of the present invention), a ridge 25b may be provided on an inner surface 25a of an annular portion (herein, referred to as the annular portion 25 of the restriction member 6), and a groove 25c may also be provided on an inner surface 25a of another annular portion (herein, referred to as the annular portion 25 of the restriction member 7). In this case, positioning the annular portion 25 of the restriction member 6 to the annular portion 25 of the restriction member 7 can be performed by fitting the ridge 25b into the groove 25c, thereby making welding easy in the third welding step.

In the foregoing embodiment, the following configuration describes the metal diaphragm damper 1: wherein the fixing of the annular portions 25 of the

restriction members

6 and 7 and the outer edge portions 20 of the

diaphragms

4 and 5 to each other by welding is further fixed by welding, and therefore the fuel pressure in the fuel chamber 11 is absorbed on both sides of the

diaphragms

4 and 5. However, the configuration is not limited thereto. For example, as in a second example modification (referred to as embodiment six of the invention) shown in fig. 11, there is provided a configuration in which the restricting member 7 is fixed to the base member 33 by a weld layer WD2 in a state where the annular portion 25 of the restricting member 7 and the plate-shaped base member 33 are brought into surface contact over the entire circumference (the outer edge portion 20 of the diaphragm 5 is fixed by the weld layer WD 1). Such a metal diaphragm damper is used in a case where the metal diaphragm damper is fixed to the top end of the fuel chamber 11 and absorbs the fuel pressure in the fuel chamber 11 only on one side of the diaphragm 5.

In the embodiment, the metal diaphragm damper 1 is described in a form in which the metal diaphragm damper 1 is provided in the fuel chamber 11 of the high-pressure fuel pump 10 to reduce pulsation in the fuel chamber 11. However, not limited thereto, the metal diaphragm damper 1 may reduce pulsation by being provided in, for example, a fuel pipe connected to the high-pressure fuel pump 10.

It is possible to provide a configuration in which the diaphragm 4 is prevented from coming into contact with the diaphragm 5 under high pressure by disposing a core material made of an elastically deformable synthetic resin, for example, in a closed space formed between the coupled diaphragm 4 and diaphragm 5 (i.e., inside the metal diaphragm damper 1).

In the embodiment, a form is described in which the first welding step and the second welding step are performed in an atmosphere made of air, and the third welding step is performed in an atmosphere made of a gas sealed in the damper body 2. The first welding step and the second welding step may also be performed in an atmosphere of gas sealed in the damper main body 2.

Description of reference numerals:

1. a metal diaphragm damper; 2. a damper main body; 3. a cover member; 4, 5, a membrane; 6, 7, a restraining member; 10. a high-pressure fuel pump; 11. a fuel chamber; 12. a plunger; 13. a suction valve; 14. a plenum chamber; 15. a discharge valve; 19. a deformable portion; 20. an outer edge portion; 20a, an outer surface; 20b, an inner surface; 25. an annular portion; 25a, an inner surface; 27. a sidewall portion; 28. a bottom; 29. a recess; 29a, recess bottom surface; 29b, a recess inner surface; 30. an aperture; 31. a support member; 31a, an opening; WD1, first and second weld layers (first weld portion); WD2, weld layer (second weld portion).

Claims

1. A metal diaphragm damper comprising:

a damper main body formed in a disc shape and including a first diaphragm and a second diaphragm, a gas being sealed between the first diaphragm and the second diaphragm, and each of the first diaphragm and the second diaphragm having a deformable portion at a center thereof;

a first restriction member provided outside the deformable portion of the first diaphragm;

a second restriction member provided outside the deformable portion of the second diaphragm;

a first welding portion provided with a first welding layer formed by welding to seal the annular portion of the first restriction member and the outer edge portion of the first diaphragm and a second welding layer formed by welding to seal the annular portion of the second restriction member and the outer edge portion of the second diaphragm; and

a second welding portion provided with a welding layer formed by welding to seal the annular portions of the first and second restriction members,

wherein each of the annular portion of the first restriction member and the annular portion of the second restriction member has a recess respectively formed in each of inner surfaces of the annular portions facing each other on a radially inner side of the annular portions;

an outer edge portion of the first diaphragm and an outer edge portion of the second diaphragm are disposed in the recesses of the first restriction member and the second restriction member, respectively, and,

the depth of the recess of the first restricting member and the recess of the second restricting member in the axial direction is substantially equal to the thickness of the outer edge portion of the first diaphragm and the outer edge portion of the second diaphragm, respectively.

2. The metal diaphragm damper according to claim 1, wherein an outer diameter of the annular portion of the first restricting member is formed larger than an outer diameter of the first diaphragm, an outer diameter of the annular portion of the second restricting member is formed larger than an outer diameter of the second diaphragm, and the second weld portion is located radially outward with respect to an outer edge portion of the first diaphragm and an outer edge portion of the second diaphragm.

3. A metal diaphragm damper comprising:

wherein the content of the first and second substances,

the first diaphragm includes a curved portion that is formed between the deformable portion and the outer edge portion of the first diaphragm and that protrudes from the annular portion of the first restriction member in a direction opposite to a protruding direction of the deformable portion of the first diaphragm in a natural state of the first diaphragm, and

the second diaphragm includes a curved portion that is formed between the deformable portion and the outer edge portion of the second diaphragm and that protrudes from the annular portion of the second restriction member in a direction opposite to a protruding direction of the deformable portion of the second diaphragm in a natural state of the second diaphragm.

4. A method of manufacturing a metal diaphragm damper, the metal diaphragm damper comprising: a damper body having a disc shape and including a first diaphragm and a second diaphragm, a gas being sealed between the first diaphragm and the second diaphragm, and each of the first diaphragm and the second diaphragm having a deformable portion at a center thereof; a first restriction member provided outside the deformable portion of the first diaphragm; a second restraining member disposed outside of the deformable portion of the second diaphragm, the method comprising:

a first welding step of fixing the annular portion of the first restriction member to the outer edge portion of the first diaphragm by welding;

a second welding step of fixing the annular portion of the second restriction member to the outer edge portion of the second diaphragm by welding; and

a third welding step of fixing the annular portion of the first restriction member and the annular portion of the second restriction member by welding after the first step and the second step.

5. The method of manufacturing a metal diaphragm damper of claim 4, wherein the first welding step and the second welding step are performed in an atmosphere made of air, and the third welding step is performed in an atmosphere made of a gas sealed between the first diaphragm and the second diaphragm.